NetBeans Architecture Answers for Tag Editor Support module

General Information

Question (arch-what): What is this project good for?
Answer:

The API allow clients to get a structural model of a document and listen on changes of the model. The model is read-only and is incrementally updated based on changes of the document content (e.g. when user edits the document). A provider has to implement an SPI (DocumentModelProvider) for a particullar document type (e.g. XML or JSP) and then register itself into the system.

Question (arch-overall): Describe the overall architecture.
Answer:

The Tag Based Editor Support is a small module based on EditorLibrary module providing DocumentModelAPI.

It consists of
• API in org.netbeans.editor.ext.tags.api
• SPI in org.netbeans.editor.ext.tags.spi
• Implementation in org.netbeans.editor.ext.tags

The API is primarily aimed to provide structural views of tags based document types like XML/JSP/HTML which contents comprise a tree structure of nested elements.

The API allows other modules to plug in their document model provider(s). DocumentModelProvider is an SPI interface implemented by other module(s) which wants to afford a structural view of a particular document type to clients. The view is then used by clients (navigator/folding etc.) to obtain and work with structure of a particullar document. The plug-ins are registered via declarative xml layers approach.

The views are tree-like structures consisting of DocumentModelElement-s. The DocumentModelElement function as a model's elements, living in a tree-like structure and describing pieces of the document. They are a kind of nodes - you can traverse through them in the tree structure and get some metadata of the related piece of document.

The heart of the API is DocumentModel which is an entry point allowing clients to get document model structure and listen on its changes.

Question (arch-usecases): Describe the main use cases of the new API. Who will use it under what circumstances? What kind of code would typically need to be written to use the module?
Answer:

API:

Code folding

uses the API to obtain a list of (XML/JSP/HTML/...) document elements and listen on the document model elements changes. The Elements are then used to manage document folds.

Navigator

gets a tree structure of a JSP/HTML/XML/... document elements and creates an appropriate nodes view in the navigator panel. Then listen on the changes of the document structure and update the tree.

Deployment Descriptor navigator

will likely use the API to select appropriate parts of the text when using the DD navigator.
The API can potentially be used by anyone who needs to get the document structure or do some mapping between the document text and the semantic of the document content.

SPI:


register_plugin

If a module wants to create a provider, it has to:
1. Create a DocumentModelProvider implementation for a particullar document type.
2. Associate it with a particullar mimetype by registering it into layer.
Question (arch-time): What are the time estimates of the work?
Answer:

Most of the work is done. The API/SPI is created, stored in cvs and is quite stable. There has to be done some simple refactorings and performance/memory consumption improvements. I expect the work can be finished in a week.

Question (arch-quality): How will the quality of your code be tested and how are future regressions going to be prevented?
Answer:

There will be a set of unit tests covering the API/SPI classes. Regression tests will be created if it's possible and appropriate.

Question (arch-where): Where one can find sources for your module?
Answer:

Sources are stored in xml/tageditorsupport module in tag_editor_support branch.

Project and platform dependencies

Question (dep-nb): What other NetBeans projects and modules does this one depend on?
Answer:

The Tag Based Editor Support module depends on: org.openide.loaders - Needed for the layer registration mechanism of providers. org.openide.filesystems - Needed for the layer registration mechanism of providers. org.openide.util - Needed for the layer registration mechanism of providers. org.openide.nodes - Needed for the layer registration mechanism of providers. EditorLib - Needed for access to the Document instance which is the DocumentModel built on.

Question (dep-non-nb): What other projects outside NetBeans does this one depend on?
Answer:

There aren't any non-netbeans modules or libraries which this module depends on.

Question (dep-platform): On which platforms does your module run? Does it run in the same way on each?
Answer:

The module does work on all platforms in the same way.

Question (dep-jre): Which version of JRE do you need (1.2, 1.3, 1.4, etc.)?
Answer:

XXX no answer for dep-jre

Question (dep-jrejdk): Do you require the JDK or is the JRE enough?
Answer:

XXX no answer for dep-jrejdk

Deployment

Question (deploy-jar): Do you deploy just module JAR file(s) or other files as well?
Answer:

XXX no answer for deploy-jar

Question (deploy-nbm): Can you deploy an NBM via the Update Center?
Answer:

XXX no answer for deploy-nbm

Question (deploy-shared): Do you need to be installed in the shared location only, or in the user directory only, or can your module be installed anywhere?
Answer:

XXX no answer for deploy-shared

Question (deploy-packages): Are packages of your module made inaccessible by not declaring them public?
Answer:

There is only org.netbeans.editor.ext.tags.DocumentModelFactoryProvider class which is not declared in public-packages.

Question (deploy-dependencies): What do other modules need to do to declare a dependency on this one?
Answer:

XXX no answer for deploy-dependencies

Compatibility with environment

Question (compat-i18n): Is your module correctly internationalized?
Answer:

XXX no answer for compat-i18n

Question (compat-standards): Does the module implement or define any standards? Is the implementation exact or does it deviate somehow?
Answer:

No new unusual standard, just layer-based xml registration and SPI interface DocumentModelProvider that clients has to implement.

Question (compat-version): Can your module coexist with earlier and future versions of itself? Can you correctly read all old settings? Will future versions be able to read your current settings? Can you read or politely ignore settings stored by a future version?
Answer:

XXX no answer for compat-version

Access to resources

Question (resources-file): Does your module use java.io.File directly?
Answer:

XXX no answer for resources-file

Question (resources-layer): Does your module provide own layer? Does it create any files or folders in it? What it is trying to communicate by that and with which components?
Answer:

XXX no answer for resources-layer

Question (resources-read): Does your module read any resources from layers? For what purpose?
Answer:

XXX no answer for resources-read

Question (resources-mask): Does your module mask/hide/override any resources provided by other modules in their layers?
Answer:

XXX no answer for resources-mask

Lookup of components

Question (lookup-lookup): Does your module use org.openide.util.Lookup or any similar technology to find any components to communicate with? Which ones?
Answer:

No, the module doesn't use Lookup.

Question (lookup-register): Do you register anything into lookup for other code to find?
Answer:

XXX no answer for lookup-register

Question (lookup-remove): Do you remove entries of other modules from lookup?
Answer:

XXX no answer for lookup-remove

Execution Environment

Question (exec-property): Is execution of your code influenced by any environment or Java system (System.getProperty) property?
Answer:

XXX no answer for exec-property

Question (exec-component): Is execution of your code influenced by any (string) property of any of your components?
Answer:

XXX no answer for exec-component

Question (exec-ant-tasks): Do you define or register any ant tasks that other can use?
Answer:

XXX no answer for exec-ant-tasks

Question (exec-classloader): Does your code create its own class loader(s)?
Answer:

XXX no answer for exec-classloader

Question (exec-reflection): Does your code use Java Reflection to execute other code?
Answer:

XXX no answer for exec-reflection

Question (exec-privateaccess): Are you aware of any other parts of the system calling some of your methods by reflection?
Answer:

XXX no answer for exec-privateaccess

Question (exec-process): Do you execute an external process from your module? How do you ensure that the result is the same on different platforms? Do you parse output? Do you depend on result code?
Answer:

XXX no answer for exec-process

Question (exec-introspection): Does your module use any kind of runtime type information (instanceof, work with java.lang.Class, etc.)?
Answer:

XXX no answer for exec-introspection

Question (exec-threading): What threading models, if any, does your module adhere to?
Answer:

XXX no answer for exec-threading

Question (security-policy): Does your functionality require modifications to the standard policy file?
Answer:

XXX no answer for security-policy

Question (security-grant): Does your code grant additional rights to some other code?
Answer:

XXX no answer for security-grant

Format of files and protocols

Question (format-types): Which protocols and file formats (if any) does your module read or write on disk, or transmit or receive over the network? Do you generate an ant build script? Can it be edited and modified?
Answer:

XXX no answer for format-types

Question (format-dnd): Which protocols (if any) does your code understand during Drag & Drop?
Answer:

XXX no answer for format-dnd

Question (format-clipboard): Which data flavors (if any) does your code read from or insert to the clipboard (by access to clipboard on means calling methods on java.awt.datatransfer.Transferable?
Answer:

XXX no answer for format-clipboard

Performance and Scalability

Question (perf-startup): Does your module run any code on startup?
Answer:

XXX no answer for perf-startup

Question (perf-exit): Does your module run any code on exit?
Answer:

XXX no answer for perf-exit

Question (perf-scale): Which external criteria influence the performance of your program (size of file in editor, number of files in menu, in source directory, etc.) and how well your code scales?
Answer:

The model creation/update time depends on the size of the underlaying document and also on its structure.

Question (perf-limit): Are there any hard-coded or practical limits in the number or size of elements your code can handle?
Answer:

No.

Question (perf-mem): How much memory does your component consume? Estimate with a relation to the number of windows, etc.
Answer:

XXX no answer for perf-mem

Question (perf-wakeup): Does any piece of your code wake up periodically and do something even when the system is otherwise idle (no user interaction)?
Answer:

XXX no answer for perf-wakeup

Question (perf-progress): Does your module execute any long-running tasks?
Answer:

XXX no answer for perf-progress

Question (perf-huge_dialogs): Does your module contain any dialogs or wizards with a large number of GUI controls such as combo boxes, lists, trees, or text areas?
Answer:

XXX no answer for perf-huge_dialogs

Question (perf-menus): Does your module use dynamically updated context menus, or context-sensitive actions with complicated and slow enablement logic?
Answer:

XXX no answer for perf-menus

Question (perf-spi): How the performance of the plugged in code will be enforced?
Answer:

The providers are supposed to plug-in an effective code. There aren't any extra mechanisms to ensure the plugins uses effective mechanisms which do not last for ages.